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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Allure 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Hard Start

Inspection/Test

Action

DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

Preliminary

Perform the Diagnostic System Check - Vehicle in Vehicle DTC Information.

Sensor/System

A variety of sensor or physical conditions may result in a hard start condition without setting a diagnostic trouble code (DTC). In order to determine if any of these conditions exist, perform the following actions:

    • Inspect for an engine coolant temperature (ECT) sensor that has shifted in value . Refer to Temperature Versus Resistance .
    • Inspect the mass air flow (MAF) sensor for proper installation. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement . A damaged MAF sensor may cause a hard start.
    • Inspect the camshaft position (CMP) sensor for proper mounting and/or a bad connection. An extended crank occurs if the powertrain control module (PCM) does not receive a CMP signal.
    • Verify proper operation of the manifold absolute pressure (MAP) sensor. Refer to Manifold Absolute Pressure Sensor Diagnosis .
    • Inspect the exhaust gas recirculation (EGR) system for proper sealing/connections and operation Refer to Exhaust Gas Recirculation (EGR) System Description .

Fuel System
    • Verify there is adequate fuel.
    • Inspect the fuel pump operation. The fuel pump should turn ON for 2 seconds when you turn ON the ignition. Refer to Fuel Pump Electrical Circuit Diagnosis .
    • Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Inspect for a restricted fuel system. Refer to Fuel System Diagnosis .
    • Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System
    • Inspect for proper ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis .
    • Remove the spark plugs and inspect for the following conditions:
       - Correct heat range
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits
       - Refer to Spark Plug Inspection .
    • Determine the cause of the conditions before replacing the spark plugs.
    • Inspect for bare or shorted ignition wires.
    • Inspect for loose ignition coil grounds.
    • Inspect the ignition control module (ICM) for proper ground connection.
    • Inspect the ignition coils for cracks or carbon tracking.
    • Soak the secondary ignition wires with water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.

Engine Mechanical

Inspect for the following conditions:

    • Excessive oil in combustion chamber or leaking valve seals--Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • Cylinder compression--Refer to Engine Compression Test in Engine Mechanical.
    • Improper valve timing
    • Combustion chambers for excessive carbon buildup--Clean the chambers using top engine cleaner. Follow the instructions on the can.
    • Incorrect basic engine parts--Inspect the following components:
       - The camshaft--Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.
       - The cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical.
       - The pistons, etc.--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical.